Structural sandwich plate members

ABSTRACT

Various rolled or extruded profiles ( 1   c   , 1   d ) with weld locations are used to connect together structural sandwich plate members comprising first and second outer metal plates ( 21  ) and an elastomer core ( 22 ) bonded to said outer metal plates ( 21 ) with sufficient strength to transfer shear forces therebetween.

[0001] The present invention relates to structural sandwich platemembers which comprise two outer metal plates and a core of plastic orelastomer material bonded to the outer metal plates with sufficientstrength to substantially contribute to the structural strength of themember.

[0002] Structural sandwich plate members are described in U.S. Pat. No.5,778,813 and U.S. Pat. No. 6,050,208, which documents are herebyincorporated by reference, and comprise outer metal, e.g. steel, platesbonded together with an intermediate elastomer core, e.g. of unfoamedpolyurethane. These sandwich plate systems may be used in many forms ofconstruction to replace stiffened steel plates and greatly simplify theresultant structures, improving strength and structural performance(stiffness, damping characteristics) while saving weight. Furtherdevelopments of these structural sandwich plate members are described inInternational Patent Application GB00/04198, also incorporated hereby byreference. As described therein, foam forms may be incorporated in thecore layer to reduce weight and transverse metal sheer plates may beadded to improve stiffness.

[0003] The structural members described in the documents referred toabove generally are simple planar members which may be flat or curved(single or double curvature) and which are welded together on site toform the desired structure, e.g. a ship, offshore structure or bridge orother civil engineering structure. In general, ships, offshorestructures or civil engineering works constructed with structuralsandwich plate members will be fabricated by first welding together thesteelwork of the largest practicable section, a hull module for example,containing one or more internal airtight cavities. The elastomer is theninjected into those cavities and cured making the section composite.Where panels, sections or modules are connected to form larger orcomplete structures, weld margins (free of elastomer) must beincorporated to mitigate or prevent damage to the elastomer from heatcaused by the welding process. When steel plates of adjacent modulescontaining structural sandwich plate members are welded together theweld margins form joining cavities. Once all welding is complete,elastomer is injected into the joining cavities to make the structurecontinuous composite construction. This method of construction placesthe cured elastomer away from sections or plates being welded. Whilstthis method provides satisfactory results, some simplification of thisconstruction method is desirable.

[0004] It is an aim of the present invention to provide structuralsandwich plate members that can more easily be assembled into ships,ship components, bridges and other civil engineering or offshorestructures.

[0005] According to the present invention there is provided a structuralsandwich plate member comprising: first and second outer metal plates;an elastomer core bonded to said outer metal plates with sufficientstrength to transfer shear forces therebetween; and an edge memberformed by a rolled or extruded profile fitted between and connected tosaid first and second outer metal plates and extending along at least apart of the periphery of said outer metal plates and said profileproviding a weld location suitable for welding said structural sandwichplate member to another structural sandwich plate member.

[0006] The materials, dimensions and general properties of the outermetal plates of the structural sandwich plate member of the inventionmay be chosen as desired for the particular use to which the structuralsandwich plate member is to be put and in general may be as described inU.S. Pat. No. 5,778,813 and U.S. Pat. No. 6,050,208. Steel is commonlyused in thicknesses of 2 to 20 mm and aluminium may be used where lightweight is desirable. Similarly, the elastomer may be any suitable, e.g.plastics, material such as polyurethane, as described in U.S. Pat. No.5,778,813 and U.S. Pat. No. 6,050,208.

[0007] The rolled or extruded profiles can be made in various forms tobe integrated into the structural sandwich plate member to allow membersto be prefabricated and made continuous into larger structures bywelding members together at the weld locations or members to metalplates (without compromising the structural integrity), simplifying insitu construction.

[0008] Profiles according to the present invention are made with rounds,fillets, dimensions and other features to provide good fatigue-resistantconnection details, connections with excellent dimensional control forease of fit up (mating of joining members) and built in weldpreparations (full or partial penetration weld preparations, backingbars and/or alignment plates) to reduce fabrication costs and tofacilitate in situ welding.

[0009] Weld locations based on the profile geometry, are locatedsufficiently away from the core material so that the welds can be madeto prefabricated members without damaging the core or being detrimentalto the member's structural characteristics. Weld locations are alsolocated away from local high stress regions which may suffer fatigueproblems.

[0010] Stiff edge profiles provide dimensional control for joining largesections or modules that advantageously eliminates the time-consumingand expensive heat faring processes associated with stiffened plateconstruction. Increased bending stiffness along joins between structuralsandwich plate members mitigates local weld distortions which simplifiesweld details and procedures, and reduces fabrication costs.

[0011] Profiles with built-in shear keys, alignment plates and frictionconnect joints simplify fit-up, thereby reducing fabrication time,labour and cost.

[0012] Profile geometries according to the present invention have beendeveloped to provide good details for typical connections between platemembers in ships, maritime, civil and offshore structures. Profiles areidentified herein by a letter or letters which classify the type ofjoint, followed by a pair of numbers indicating a critical dimension andthe approximate mass of the profile in kilograms per metre of length.For example, E 40×17 is a typical edge profile for a structural sandwichplate member with a 40 mm thick core and has a mass of 17 kg/m. Thefollowing table lists some exemplary profile types, gives a briefdescription and describes their application or use. Profile TypeDescription/Use E Edge or perimeter profile for connecting largesections or modules that require alignment of ± 5 mm along matchingedges on sections measuring up to 50 m by 70 m in cross- section orweighing up to 500 T. SM, SF Male and female socket profiles fittedaround the perimeter of structural sandwich plate members to connectplate members directly to form larger plate members or indirectlythrough SP or CP profiles. P Plate profile which is integrated intostructural sandwich plate members and is used to connect to all-metalwebs of transverse and longitudinal girders or bulkheads. T T Integralthrough-thickness plate profile for transferring force directly throughthe structural sandwich plate member. S Spacer profile to connect andproperly space at the specified core thickness metal plates to formstructural sandwich plate members. Spacer profiles provide a landingplate combination backing bar for welding plate seams. SP Sandwich panelprofiles which are typically used to connect structural sandwich panelmembers together to form larger sections or modules, for example decksto side-shell or hull structure to bulkheads. CP Complex profiles forconnecting multiple structural sandwich and metal plate members.Geometries are specific to the given application. Typical examplesinclude: inner bottom/hopper/girder; hopper/side shell/web frame; andstool/inner hull/transverse floor connections. T Transition profiles forconnecting existing metal plates to structural sandwich plate members oras a transition section for a structural overlay.

[0013] Structural sandwich plate members according to the invention maycontain one or more cavities and one or more profile types as requiredfor the application and the method by which they are to be connected(welded) to form the complete ship or structure.

[0014] The structural profiles, shapes or sections of the invention aregenerally roll-formed from steel or extruded from aluminium and willalmost always be of the same metal as that used to form the outer platesof the structural sandwich plate members of which they form part. Theprofiles are generally elongate and extend for substantially all of theperimeter, length and/or width of the structural sandwich plate membersand/or metal plates which they join.

[0015] It should be noted that the various profiles according to theinvention may be used with structural sandwich plate members asdescribed in the documents referenced above as well as those accordingto the present invention.

[0016] The present invention will be described below with reference toexemplary embodiments and the accompanying drawings, in which:

[0017]FIGS. 1A to C are cross-sections of edge profiles used instructural sandwich plate members according to the present invention;

[0018]FIGS. 2A and B are cross-sectional views illustrating two ways inwhich the edge profiles of FIG. 1C can be used to connect modulescomprised of structural sandwich plate members or structural sandwichplate members according to the present invention;

[0019]FIGS. 3A and B are cross-sectional views illustrating deep maleand female socket profiles according to the present invention and theirmanner of use;

[0020]FIGS. 4A and B are cross-sectional views illustrating shallow maleand female socket profiles according to the present invention and theirmanner of use;

[0021]FIGS. 5A to D are cross-sectional views illustrating various plateprofiles for connecting structural sandwich plate members to aperpendicular metal plate;

[0022]FIG. 6 is a cross-sectional view illustrating a through-thicknessplate profile for direct force transmission;

[0023]FIGS. 7A and B are cross-sectional views illustrating twoalternative spacer profiles for constructing structural sandwich platemembers according to the present invention;

[0024]FIGS. 8A to G illustrate various structural sandwich panelprofiles for joining together multiple prefabricated structural sandwichplate members, e.g. members used to form the deck and side shellconnections, bulkhead to hull connections of a bulk carrier, containervessel, tanker, etc., and their manner of use;

[0025]FIGS. 9A to J are cross-sectional views of various complexprofiles according to the present invention and their manner of use forconnecting multiple structural sandwich plate members and metal platesor multiple structural sandwich plate members at acute and obtuseangles;

[0026]FIGS. 10A to D are cross-sectional views of transition profilesfor transition connections between a structural sandwich plate memberand a conventional stiffened metal plate;

[0027]FIG. 11 is a mid-tank cross-section of a product oil tankerconstructed using structural sandwich plate members according to thepresent invention and identifies the type and location of differentprofiles;

[0028]FIG. 12 is a mid-tank longitudinal section of the product oiltanker of FIG. 11;

[0029]FIG. 13 is an exploded view showing the structural components of amid-tank section of the product oil tanker of FIG. 11;

[0030]FIG. 14 is a partly-exploded perspective view with enlargedportions showing a structural sandwich plate member with integratedstructural profiles according to the present invention and itsconnection to a longitudinal upstanding metal web; and

[0031]FIG. 15 is a partly-sectioned perspective view of two mid-tanksections of the product oil tanker of FIG. 11 which illustrates edgeprofiles and their manner of use for connecting two tank sectionmodules.

[0032] In the various drawings, like references denote like parts.

[0033]FIGS. 1A to C illustrate edge profiles 1 a to c which generallyform the outward edge of a structural sandwich plate member such that,when a number of such plate members are formed into a large section ormodule, the outward edge of that module is largely comprised of edgeprofiles that can be mated and joined by welding the welding location onthe outward edge of an adjacent module. In general, the edge profilesinclude built-in backing bars and full or partial penetration grooveweld preparations at the possible weld locations to eliminate the needof providing or making these in situ. These sections may be roll formedor fabricated from standard shapes and plates in steel. Alternativelythey may be extruded in aluminium for applications where light weight isdesired, e.g. the upper decks of cruise ships or for hull forms in fastships. Of course, other metals may be used if desired and structuralprofiles of different metals may be used together to form structuralsandwich plate members according to the invention.

[0034] The edge profile 1 a shown in FIG. 1A, which is a lateralcross-section, comprises a generally planar portion (long flange) 11which will form part of one outer plate of a structural sandwich platemember and has sufficient length that the tip can be displaced (e.g. byup to ±5 mm) to be aligned with the adjacent module. Placed inwardlyfrom one edge of the section is an upstanding web 12 which will extendacross the thickness of the structural sandwich plate member. At thedistal end of the upstanding web 12, a short flange 13 parallel to thelong flange 11 and extending towards its centre is provided. Shortflange 13 provides a landing surface for the metal plate used tocomplete the structural sandwich plate member. Full penetration grooveweld preparations 14 are provided at the edges of the long flange 11 toenable an adjacent plate or edge profile to be welded to the edgeprofile from the exterior. As can be seen in the subsequent description,possible weld locations include the full penetration groove weldpreparations 14 and the end of the short flange 13.

[0035]FIG. 1B illustrates an alternative edge profile 1 b similar tothat of FIG. 1A and again comprising a plate portion (long flange) 11,upstanding web 12 and short flange 13. In this case, the weldpreparations 14 of the long flange 11 enable an adjacent plate or likesection to be welded to the edge profile 1 b from the interior. FIG. 1Cillustrates a further alternative edge profile 1 c which again consistsof (long flange) plate portion 11, upstanding web 12 and short flange 13performing the same functions as in the sections 1 a, 1 b of FIGS. 1Aand B. In edge profile 1 c of FIG. 1C, the upstanding web 12 is locatedadjacent one side edge of the long flange 11. The edge weld preparation14 on the other side may be arranged to enable welding from theexterior, as shown, or to enable welding from the interior, as desiredfor the intended fabrication sequence. At the base of the upstanding web12, a small projection 17 is provided, with its lower surface alignedwith the inner surface of the long flange 11, to act as a backing bar toreceive an adjacent plate. As can be seen in the subsequent description,possible weld locations include the small projection 17, weldpreparation 14 and the short flange 13.

[0036] It should be noted that in the above and following descriptions,the terms “interior” and “exterior” are used to identify preferred welddirection with respect to their intended location in a structure. InFIGS. 1A to C, the exterior surface of the profile is the lower surfaceand the interior, the upper surface.

[0037]FIGS. 2A and B illustrate two alternative ways in which profilesas shown in FIG. 1C can be used to connect large sections or modulescomprised of structural sandwich plate members.

[0038] In the arrangement of FIG. 2A, two sections or modules 2 a, 2 bare constructed of structural sandwich plate members comprising outermetal plates 21 bonded together by an elastomer core 22 whichsubstantially contributes to the structural strength of the member. Theedges of the sections 2 a, 2 b are closed by an edge profile 1 c, onesection 2 a has the long flange 11 of the edge profile 1 c downwards (asillustrated) and the other section 2 b has the planar portion 11 upwards(as illustrated). The two sections 2 a, 2 b are fitted together with thefree end of the long flange 11 of each edge profile 1 c supported by theshort flange 13 of the other edge profile 1 c. Full penetration groovebutt welds 4 b are made to connect the adjacent modules together at theweld location. The newly-formed cavity 5 is then injected with elastomerto make the construction continuous. If necessary, the degree of overlapbetween the short flange 13 of one section and the long flange 11 of theother can be varied to accommodate normal variations in fit-up that areassociated with making modules.

[0039] In the arrangement of FIG. 2B, two like edge profiles 1 d similarto that shown in FIG. 1C are again used. In this case, the edge profiles1 d are positioned with their long flanges 11 on the same side. The weldpreparation as shown in FIG. 2B allows the finishing butt weld 4 b to bemade at the weld location from the interior. Subsequently plate 6, whichpreferably has the same thickness as the outer plates 21 of modules 2 a,2 b, is welded 4 b at the weld location to close cavity 5, with theshort flanges 13 acting as landing surfaces and backing bars. Cavity 5is then injected with elastomer to make the connecting plate segmentcomposite. This method of connection between modules allows for greatervariations in alignment than the method of FIG. 2A.

[0040] In FIGS. 2A and 2B, as well as various of the other figuresdescribed below, butt welds made prior to casting of elastomer for thestructural sandwich plate members are indicated at 4 a. Finishing welds,that join structural profiles and plate members, are indicated at 4 bbut not all are shown completed.

[0041]FIGS. 3A and B illustrate the deep male and female socket profilesand their use to align and join adjacent structural sandwich platemembers.

[0042] As shown in FIG. 3A a male socket profile 71 and female socketprofile 72 have complimentary U-shapes that mate, providing alignmentand shear capacity between joining prefabricated structural sandwichplate members. The total depth of the webs of the male and female socketprofiles 71, 72 are equal to the core thickness of the sandwich platemember in the edge of which they are fitted. As shown, the twostructural sandwich plate members have the same thickness but the socketprofiles may be varied to connect together structural sandwich platemembers of different thicknesses or different metal plate thicknesses.The socket profiles may extend for some or preferably all of the entirelengths of the edges of the structural sandwich plate members and arewelded to metal plates 21 by fillet welds 4 a as illustrated in FIG. 3Bto form metal boxes with enclosed air-tight cavities. Other profiles mayalso be integrated into the cavities or used along the edges. Thesecavities are injected with elastomer 22 and after curing form structuralsandwich plate members. Larger sections can be made by mating the maleand female socket profiles 71, 72 along the edges of adjacent platemembers at the weld locations, as shown in FIG. 3B and making themcontinuous by welding butt welds (not shown). The deep socket profilesneed not be fully butted, as shown in FIG. 3B, but may have a gapbetween profiles to accommodate misalignment within the plane of theplate members.

[0043]FIGS. 4A and B illustrate shallow male and female socket profiles73, 74 which form one or more edges of a structural sandwich platemember and are used in the same manner as the deep socket profiles 71,72.

[0044]FIGS. 5A to D illustrate various plate profiles that areintegrated into structural sandwich plate members and that are used toconnect structural sandwich plate members that are in generalperpendicular to a metal web.

[0045]FIG. 5A illustrates the basic form of a plate profile 81. Thelower part of the profile 81 is shaped like an I-beam with upper andlower flanges 811, 812. A web extends above the upper flanges. Theflanges 811, 812 act as landing surfaces and backing bars to allow theouter metal plates 21 of structural sandwich plate members 2 a, 2 b tobe welded to the plate profile 81 with butt or full penetration groovewelds 4 a. The web extending above the upper flanges 811 is used as aweld location to connect to the perpendicular metal web.

[0046] Subsequent to welding of all edge and integrated profiles toplates 21, elastomer 22 is injected into the cavities to form thestructural sandwich plate members 2 a, 2 b. Conventional metal plates orwebs 61 are welded to the plate profile 81 at the weld location witheither full penetration groove welds or butt welds 4 b that are locatedsufficiently away from the core as not to damage it by the weldingprocess.

[0047] Variations of the plate profile form with different dimensions,built-in weld preparations, backing bar and alignment plate arrangementsare illustrated in FIGS. 5B, 5C and 5D. Plate profiles 82 and 83, shownin FIG. 5B and 5C respectively, are simplified and have one set oflanding surfaces/backing bars for the interior one of plates 21. Theprofile is fillet welded to the exterior one of plates 21 and welded tothe web 61 at the weld location with either a one-sided full penetrationgroove weld or with two-sided partial penetration groove welds. Theplate profile 84 shown in FIG. 5D is similar to profile 82 but has anadditional backing bar alignment plate 842 to facilitate the welding ofthe web 61 at the weld location.

[0048]FIG. 6 illustrates a through-thickness profile 85 which can beused to transfer force directly through structural sandwich platemembers. The through-thickness profile 85 comprises a plate of constantthickness from which project two spaced apart pairs of flanges 851, 852.These flanges 851, 852 act as landing surfaces and backing bars forplates 21 forming the outer plates of structural sandwich plate elements2 a, 2 b which are welded to it. Webs or other conventional metal platescan be welded at weld locations to the through-thickness profile 85 ofthe precast structural sandwich panel during construction.

[0049] Spacer profiles 91 and 93, shown in FIGS. 7A and 7B, can be usedto act as a landing surface and backing bar 92 for making plate seamsand to space apart plates 21 which form the outer plates of structuralsandwich plate members. Spacer profiles 91 and 93 are I-shaped andT-shaped respectively. Each is first welded with fillet welds to theexterior plate and then to the interior plates at a weld location whenthe plate seam is welded.

[0050] Various sandwich plate profiles 101 to 107 for joining mutuallyperpendicular structural sandwich plate members are shown incross-section in FIGS. 8A, whilst their manner of use is shown in FIGS.8B to 8D. These sandwich plate profiles may also be referred to as nodalprofiles.

[0051] In FIG. 8B three prefabricated sandwich plate members areconnected together with two aligned and the third extendingperpendicularly from them and is representative of a typical deck toside shell connection detail. The nodal profile 101 used to effect thisconnection is a roll-formed or extruded section of metal having socketsfacing the directions of the structural sandwich plate members which areto be connected. The overall form is H-shaped with the third socketformed by flanges provided on one of the uprights of the H. A malesocket profile 102 forming the edge of the prefabricated structuralsandwich plate members is inserted into the nodal profile 101 and weldedat weld locations to form a continuous structure as shown in FIG. 8C.Finishing welds (not shown) make the joint continuous. Localised weldingcan be carried out without affecting the structural integrity of thejoint.

[0052]FIGS. 8D and 8E illustrate the method of use of two nodal profiles103 and 104 that are used to connect two prefabricated structuralsandwich plate members and are again representative of a typical deckside shell construction detail. Nodal profiles 103 and 104 provide aright angle connection with a square outer corner and a chamfered outercomer, respectively. In both cases, the profiles are generally U-shapedwith small perpendicular plate protrusions on the outside face of oneleg which form the second socket.

[0053]FIG. 8F illustrates the method of use for sandwich plate profile107 that would be used to connect four prefabricated structural sandwichplate members and is representative of a typical inner hull stoolbulkhead connection.

[0054]FIG. 8G illustrates the method of use for the sandwich plateprofile 106 which is integrated into one structural sandwich platemember and subsequently made continuous with two other precaststructural sandwich plate members by welding at weld locations. Again,finishing welds are omitted for clarity. In this case, the nodal profile106 is basically a structural angle with inner small plate protrusionswhich are perpendicular to the outside face of the legs of the angle.The small plates provide alignment, socket and weld details foraccepting two precast structural sandwich plate members.

[0055] Although not illustrated by any of the profiles in FIG. 8, it ispossible to vary the geometry of the profile to change the alignment ofthe prefabricated structural sandwich plate member from being orthogonalto any other angle. Also, it is preferable with all of the arrangementsof FIGS. 8A to G that finishing welds result in smooth outer surfaces tothe joints, filling in the gaps between outer plates 21 and the flangesto the nodal profiles.

[0056] Arrangements to connect angled structural sandwich plate membersto each other and to conventional plates in which at least one platemember is framed into the joint at an oblique angle are shown in FIGS.9A to J. The connections of FIGS. 9A to G are representative of typicalconnection between a hopper, inner hull bottom and a longitudinalgirder, or between the side shell, hopper-side shell and a stringer.Those of FIGS. 9H, I and J can be used for hopper to inner hull bottomto stool connections. FIGS. 9A to E illustrate complex profiles that areintegrated into the steel fabrication process prior to the injection ofelastomer and their manner of use whilst FIGS. 9F and 9G illustratecomplex profiles that join precast structural sandwich plate members.

[0057] The working line or centroid of all plate members framing intothe connection are aligned to act through the same point so that noeccentric forces act on the profile.

[0058]FIG. 9A illustrates a basic form of a complex profile 110 which isused to connect an inclined structural sandwich plate member, ahorizontal structural sandwich plate member and a vertical metal plate.The complex profile 110 essentially comprises a vertical plate portionwhich is to be aligned with and butt welded to a vertical metal plate ata weld location. Four flanges 111-114, extending from the vertical plateportion a distance sufficient to place joining welds to outer plates 61in a lower stress range region (for better fatigue resistance) arespaced apart and oriented to align with the outer plates 21 of theinclined and horizontal structural sandwich plate members. The outerplates 21 of the structural sandwich plate members are butt welded tothe respective tips of flanges 111-114. The extension of the verticalmetal plate through the core depth of the structural sandwich platemembers transmits the through-thickness forces associated with thevertical force component in the inclined structural sandwich platemember.

[0059]FIGS. 9B, 9C and 9D are variations of the basic form of thecomplex profile which include different weld preparations. The flangetips of flanges 121-124 and 131-134 of complex profiles 120 and 130 inFIGS. 9B and 9C have been bevelled for full penetration groove welds tomade form the outside or all from above, respectively. Complex profile120 in FIG. 9D has integrated backing bars 145 which provide the landingsurface and alignment necessary to make butt welds between the outerplates 21 and the complex profile 140 from the preferred directions.Complex profile 150 in FIG. 9E is a variant of complex profile 140 withsolid core 151 having side faces 152, facing the structural sandwichplate members and rolled notches 153 that provide the same function asbacking bars.

[0060]FIGS. 9F and 9G illustrate two additional variations of the basicform of the complex profile in FIG. 9A that would be used to joinprefabricated structural sandwich plate members to conventional metalplates. FIG. 9G illustrates the use of a solid metal block or bar 107 asan alternative male socket member to the U-shaped profile and the samesolid core variation 171 as illustrated in FIG. 9E. Although notillustrated, complex profiles may be provided that are integrated intoone or more structural sandwich plate members and provided with one ormore sockets for connection to one or more prefabricated structuralsandwich plate members.

[0061]FIGS. 9H, I and J illustrate a variety of complex profiles 180,190, 200 for typical hopper to inner hull bottom to stool connectionsand their manner of use for joining prefabricated structural sandwichplate members and conventional metal plates. In each case, appropriatelyoriented and spaced flanges 181, 182, 191, 192, 201, 202 are provided toform sockets to receive male socket members 102, 105 provided in theends of the structural sandwich plate members and webs 183, 193, 203transmit through-thickness forces.

[0062]FIGS. 10A to C illustrate transition profiles 210, 220, 230 whichare used to connect a structural sandwich plate member to an alignedconventional metal plate or web.

[0063] As shown in FIG. 10A, transition profile 210 essentiallycomprises two plate portions 211, 212 which are joined together at oneedge, where they are to be welded to the conventional metal plate 73 ata weld location. The upper plate portion 211 is parallel and alignedwith the conventional metal plate 73 where as the lower plate portion212 is inclined so that at the distal edges of the plate portions 213,214 they are spaced apart by a distance equal to the thickness of thestructural sandwich plate member to which the outer plates 21 arewelded. The distal end portion 213 of plate portion 212 is made parallelto the other plate portion 211 and the outer plate of the structuralsandwich plate member to which it is to be connected. The distal endportions of the plate portions 211, 212 are also provided with backingbars 214 to assist in welding the outer plates 21 of the structuralsandwich plate member to transition profile 210.

[0064] Transition profile 220 shown in FIG. 10B is a very similar totransition profile 210 of FIG. 10 A but the upper link member 221 isshortened so that the points of connection between plate portions 221,222 and the respective outer plates 21 of the structural sandwich platemember are not aligned vertically and in which an additional backing bardetail has been included to facilitate the welding of the transitionprofile to the metal plate 73 at the weld location.

[0065] Transition profile 230 shown in FIG. 10C is for use where theexisting plate 74 extends to form one of the outer plate members of thestructural sandwich plate member, as in the case of structural overlays.The lower plate portion 231 is placed against and welded at its edges toplate 74. The upper plate portion 232 is joined at one edge to one edgeof lower plate portion 231 and rises up so as to be spaced from lowerplate portion 231 for connection to plate 21 which forms the other outerplate of the structural sandwich plate member.

[0066] A fourth transitional profile 240 is shown in FIG. 10D and issimpler to roll-form. Transitional profile 240 comprises a head portion241, a main angled plate 242 and a tail portion 243. The head portionhas a backing bar 244 and weld preparation 245 at a weld location forconnection to an existing metal plate 73 as well as a shoulder 246 toreceive one outer metal plate 21 of the structural sandwich plateelement. The tail portion 243 has a backing bar 247 for receiving theother outer metal plate 21 whilst the main angled plate 242 makes thetransition from the existing metal plate 73 to the full thickness of thestructural sandwich plate member.

[0067] It will be appreciated that in describing the various profiles ofthe invention, directional terms such as “upper”, “above” and“horizontal”, etc., have been used with reference to the orientation ofthe various parts shown in the drawings. Of course, the various partscan also be used in other orientations, as desired. It will also beappreciated that the various profiles will be rolled or extruded withthe shapes, dimensions and weld preparations that are satisfactory forboth structural and economic considerations.

[0068] A mid-tank section of a 40,000 DWT product oil tanker 300 isshown in FIGS. 11 to 15 as an example of the use of structural sandwichplate members and structured profiles according to the presentinvention. FIG. 11 is a mid-tank cross section of the tanker 300 withthe left hand part showing longitudinal framing and the right hand partshowing a typical transverse frame. FIG. 12 is a longitudinal sectionfor a portion of tank section along a longitudinal frame. FIG. 13 is anisometric exploded view of a typical tank section. FIG. 14 is apartially exploded view with enlarged portions showing the use ofprofiles according to the invention to connect a structural sandwichplate member, e.g. forming part of the inner or outer hull, to aperpendicular plate, e.g a longitudinal or transverse framing plate.FIG. 15 is a perspective view of two hull sections with an enlargedportion showing the use of edge profiles according to the invention tojoin the modules.

[0069] For this particular example the deck plate 311, outer hull 302,303, 310, 314 and inner hull 304, 305, 316, 317 would be constructedwith structural sandwich plate members. The corrugated bulkhead 315,longitudinal framing 306, 307, 312 and transverse framing 308, 309, 313would be constructed with metal plates. Profiles according to thepresent invention, described above and illustrated in FIGS. 1 to 10would be used to join these members. All members are made continuous bywelding and according to the present invention a significant number ofstructural sandwich plate elements may be prefabricated and subsequentlywelded together at a weld location on site.

[0070] In particular, the plate profiles 81, 82, 83, 84 shown in FIGS.5A to D can be used to connect a longitudinal or transverse framingplate 306, 307, 308, 309, 312, 313 to a structural sandwich plate member2 d forming part of the inner or outer hulls 302, 303, 304, 305, 310,314, 316, 317. An example of connection of a longitudinal framing plateis shown in greater detail in FIG. 14. As can there be seen, thestructural sandwich plate member 2 d is made up from three elongatesteel plates 21 a, 21 b, 21 c of which the largest 21 a forms theoutermost layer of the outer hull or the innermost layer of the innerhull. Edge profiles 1 a, 1 b, or 1 c are welded along the short edges ofthe plate 21 a, these edges will form the edge of a hull section inwhich the structural sandwich plate member 2 d is to be incorporated andfacilitate connection of hull sections as described above. Along thelong edges of the plate 21 a, socket profiles 71, 72 are welded tofacilitate connection of the structural sandwich plate member 2 d toadjacent members in the hull section. The plate profile 81, 82, 83 or 84is welded along the centre line of plate 21 a. Plates 21 b and 21 c canthen be welded in place with the edge profiles 1 a, 1 b, 1 c, or 1 d,socket profiles 71, 72 and backing bars on the plate profile 81, 82, 83or 84 supporting the plates 21 b, 21 c. With the plates 21 b, 21 c inplace, two air-tight cavities are formed and these are then injectedwith elastomer to complete the structural sandwich plate member. Theframing plate 306, 307 can then be welded to the plate profile 81 at thewelding location which projects far enough from the structural sandwichplate member 2 d to prevent the heat of welding damaging the elastomer.It will be appreciated that the construction of the structural sandwichplate member 2 d and optionally also the connection of the longitudinalframing plate 306, 307 can be carried out in a factory rather than ashipyard, enabling improved dimensional accuracy and higher qualityconstruction through well cured elastomer and good welds.

[0071] Other examples of the use of profiles according to the inventionin the vessel of FIGS. 11 to 15 are:

[0072] complex profiles 110, 120, 130, 140, 150, 160, 170 to connectinner hull bottom 305 to hopper 318 to a longitudinal framing plate 307or inner side shell 304 to hopper 318 to a longitudinal framing plate306;

[0073] sandwich plate profiles 101 to 107 to connect deck 311 to sideshell 304; and

[0074] complex profiles 180, 190, 200 to connect hopper 318 to innerhull bottom 305 to stool 316.

[0075] As mentioned above, edge profiles according to the invention canbe employed to facilitate connection of hull sections or modules ofother structures, allowing the modules or sections to be constructedoff-site for convenience and improved dimensional accuracy. This isillustrated in FIG. 15 which shows the connection of two hull modules401, 402 of the vessel 300. The modules 401, 402 are constructed so thatthe edges of the structural sandwich plate members which form the edgesof the sections are provided with edge profiles 1 c. When the twomodules 401, 402 are brought together, the free edges of the longflanges 11 of the edge profiles 1 c can be displaced as necessary toline up against the end of the short flange of the edge profile 1 c onthe other section. Simply welding the long flanges to the short flangesat the weld location assisted by the built-in weld preparations, joinsthe two sections and forms cavity 5 which is subsequently injected withelastomer to form a composite structure.

[0076] Whilst we have described above exemplary embodiments of theinvention, it will be appreciated that this description is not intendedto be limitative and that variations and modifications may be made tothe described embodiments without departing from the scope of theinvention defined in the appended claims.

1. A structural sandwich plate member comprising: first and second outermetal plates; an elastomer core bonded to said outer metal plates withsufficient strength to transfer shear forces therebetween; and an edgemember formed by a rolled or extruded profile fitted between andconnected to said first and second outer metal plates and extendingalong at least a part of the periphery of said outer metal plates andsaid profile providing a weld location suitable for welding saidstructural sandwich plate member to another structural sandwich platemember.
 2. A structural sandwich plate member according to claim 1wherein said edge member comprises a first flange substantially coplanarwith said first outer metal plate, a web upstanding from said firstflange and a second flange extending parallel to said first flange fromthe end of said web and at least partially lying against said secondouter plate.
 3. A structural sandwich plate member according to claim 2wherein said web is upstanding from one edge of said first flange.
 4. Astructural sandwich plate member according to claim 3 wherein said edgemember further comprises a third flange substantially parallel to saidfirst flange and projecting from said web in the opposite direction tosaid first flange, said third flange being positioned to act as abacking bar for welding said first outer plate to said edge member.
 5. Astructural sandwich plate member according to any one of claims 2 to 4wherein at least one edge of said first flange is provided withpreparations for butt welding to another flange or plate.
 6. Astructural sandwich plate member according to any one of claims 2 to 5wherein said second flange extends beyond the edge of said second outerplate to act as a support for welding another plate or flange to saidstructural sandwich plate member.
 7. A structural sandwich plate memberaccording to claim 1 wherein said edge member is U-shaped incross-section having a base portion and two arms with the arms of the Ubeing substantially parallel to and at least partially lying againstsaid first and second outer plates.
 8. A structural sandwich platemember according to claim 7 wherein the base portion of said edge memberprojects outwardly from the edges of said first and second outer platesso as to be engageable in a socket.
 9. A structural sandwich platemember according to claim 7 wherein the base portion of said edge memberis spaced inwardly from the edges of said first and second outer platesso as to form a socket.
 10. A structural sandwich plate member accordingto claim 1 wherein said edge member comprises an inclined flange formingan acute angle to said first outer metal plate and connected at firstand second edges to said first and second outer metal platesrespectively.
 11. A structural sandwich plate member according to claim10 wherein said edge member further comprises a head portion connectedto said first edge of said inclined flange, said head portion havingweld preparations for butt welding to another plate or flange that isaligned with said first outer metal plate.
 12. A structural sandwichplate member according to claim 11 wherein said inclined flange isconnected to said first flange via said head portion.
 13. A structuralsandwich plate member according to claim 12 wherein said edge memberfurther comprises a further flange substantially parallel to said firstouter plate and connected at a first edge to said head portion.
 14. Astructural sandwich plate member according to claim 13 wherein saidfurther flange is butt welded at a second edge thereof to said firstouter plate so that said inclined flange is connected to said firstouter plate via said head portion and said further flange.
 15. Astructural sandwich plate member according to claim 13 wherein saidfurther flange overlies said first outer plate.
 16. A structuralsandwich plate member according to claim 15 wherein said first outerplate is an existing metal plate of a structure to which the structuralsandwich plate member is retro-fitted.
 17. A structural sandwich platemember according to any one of claims 10 to 16 wherein said inclinedflange has a tail portion at its second edge that is substantiallyparallel to said second outer plate.
 18. A structural sandwich platemember according to any one of the preceding claims comprising aplurality of like or different edge members extending along respectiveparts of the periphery of said outer metal plates.
 19. A structuralsandwich plate member according to any one of the preceding claimswherein the said edge member or members extend along substantially theentire periphery of said outer metal plates.
 20. A structural sandwichplate member comprising first and second outer metal plates; anelastomer core bonded to said outer metal plates with sufficientstrength to transfer shear forces therebetween; and a connection memberformed by a rolled or extruded profile and joined between said first andsecond outer metal plates.
 21. A structural sandwich plate memberaccording to claim 20 wherein said connection member comprises a webabutting said first outer plate and projecting through said second outerplate.
 22. A structural sandwich plate member according to claim 20wherein said connection member comprises a web projecting through bothsaid first and second metal plates.
 23. A structural sandwich platemember according to claim 21 or 22 wherein said connection memberfurther comprises at least one flange projecting from said web to act asa backing bar for welding one of said outer plates to said web.
 24. Astructural sandwich plate member according to claim 21, 22 or 23 whereinthe or an edge of said web projecting through one of said outer metalplates has preparations for butt welding to a coplanar metal plate. 25.A structural sandwich plate member according to claim 20 wherein saidconnecting member comprises an I-beam or a T-beam extendingperpendicular to and between said first and second metal plates.
 26. Astructural part comprising at least first and second structural sandwichplate members, each comprising first and second outer metal plates andan elastomer core bonded to said outer metal plates with sufficientstrength to transfer shear forces therebetween, joined together by alink member formed by a rolled or extruded elongate profile.
 27. Astructural part according to claim 26 wherein said link member comprisesa plate portion having projecting therefrom first to fourth flanges,said first to fourth flanges being coplanar with respective ones of saidfirst and second outer plates of said first and second structuralsandwich plate members.
 28. A structural part according to claim 26wherein said link member comprises a solid portion having first andsecond faces, said first and second faces having bevelled edges to whichthe outer plates of said first and second structural sandwich platemembers are connected.
 29. A structural part according to claim 28wherein said link member further comprises a plate portion extendingfrom said solid portion, not from either of said first or second faces.30. A structural part according to claim 27 or 29 wherein one edge ofsaid plate portion is provided with weld preparations for butt weldingto another plate or flange.
 31. A structural part according to claim 26wherein at least one of said first and second structural sandwich platemembers comprises an edge member formed by a rolled or extruded profileand projecting beyond the edges of said outer metal plates; and saidlink member comprises at least one socket to receive said edge member32. A structural part according to any one of claims 26 to 31 whereinsaid first and second structural sandwich plate members are notparallel.
 33. A vessel, off-shore or civil engineering structure,section or module including at least one structural sandwich platemember according to any one of claims 1 to 25 or a structural partaccording to any one of claims 26 to
 32. 34. An edge member for use witha structural sandwich plate member comprising: first and second outermetal plates and an elastomer core bonded to said outer metal plateswith sufficient strength to transfer shear forces therebetween; saidedge member being formed by a rolled or extruded profile and adapted tobe fitted between said first and second outer metal plates and extendalong at least a part of the periphery of said outer metal plates andproviding a weld location.
 35. An edge member according to claim 34provided with weld preparations at the weld location for assisting inwelding said outer metal plates to said edge member.
 36. A connectionmember for use with a structural sandwich plate member comprising firstand second outer metal plates and an elastomer core bonded to said outermetal plates with sufficient strength to transfer shear forcestherebetween; said connection member formed by a rolled or extrudedprofile and adapted to be joined between said first and second outermetal plates.
 37. A link member for joining at least first and secondstructural sandwich plate members, each comprising first and secondouter metal plates and an elastomer core bonded to said outer metalplates with sufficient strength to transfer shear forces therebetween,said a link member formed by a rolled or extruded profile and having aweld location.
 38. A structural sandwich plate member constructedsubstantially as hereinbefore described with reference to theaccompanying drawings.